Bermudagrass Hay Intake of Beef Cattle Supplemented with Corn or Soybean Hulls
2008
St. Louis, David G. | McCormick, Michael E.
Three supplementation trials were conducted to test the accuracy of National Research Council dry matter intake (DMI) predictions. 'Alicia' bermudagrass (Cynodon dactylon) hay was fed ad libitumwith cracked corn (Zea mays) or soybean hulls (Glycine max) as energy supplements. Three treatments in each trial were: bermudagrass hay plus cracked corn at 0.8% of body weight (BW) (BG + C); bermudagrass hay plus soybean hulls at 1.6% of BW (BG + H); and a control treatment of hay alone (BG). Diets BG + C and BG + H were predicted to provide equal amounts of energy because supplements were expected to substitute for DMI of hay. In the three trials, using cows and heifers and hay of two different qualities, diets were not equal in energy because supplements were mostly additive to hay DMI. In Trial 1, cow DMI of hay was 1.82, 1.63, and 1.79% BW for BG + C, BG + H, and BG, respectively. In Trial 2, DMI for cows was 1.14, 1.15, and 1.23% BW for BG + C, BG + H, and BG, respectively. Heifers in Trial 3 had similar DMI as cows. The Beef NRC equations, from which these diets were formulated, overestimated DMI of hay alone and were not accurate in predicting the additive and substitutive effects of supplementation.
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